1. Technical Field
The present invention relates to wastewater treatment systems.
2. Background Information
To meet local health and water regulations in areas where no municipal waste treatment hook-ups are available, household wastewater treatment systems should be capable of converting a stream of wastewater into a condition suitable for discharge into the surrounding ecosystem. However, there are regions where soil conditions do not permit the use of conventional septic systems.
Alternatives to septic systems are available that can treat wastewater to a quality suitable for above-ground discharge. However, due to their size, cost and complexity, these systems typically require custom-solution engineering and as such are predominantly used for industrial wastewater treatment. These systems may contain a number of optional components, including components to stage the waste stream, meter the flow into a digester, digest the impurities, clarify the effluent, and ultimately disinfect the output stream, depending on the treated water quality to be obtained.
One type of digester that may be used in such a wastewater treatment system is a rotating biological contactor (RBC). An RBC may be a stack of parallel plates on a rotating shaft or may be a rotating enclosure containing a plurality of media onto which aerobic bacteria can attach. Examples of RBCs are disclosed in U.S. Pat. No. 5,350,507 to McManus; U.S. Pat. No. 4,137,172 to Sako et al.; U.S. Pat. No. 4,200,532 to Iwatani et al.; and U.S. Pat. No. 4,333,893 to Clyde. Examples of such media are disclosed in U.S. Pat. No. 5,401,398, to McManus. The above references are hereby incorporated herein by reference. RBCs host aerobic bacteria and provide those bacteria with a continual supply of all life-supporting ingredients by exposing them to effluent, their source of food, and air, their source of oxygen. These bacteria may then be used to digest impurities in a stream of wastewater.
These prior wastewater treatment systems have several disadvantages. First, they consist of several individual components that must be separately transported, installed and maintained. Second, they consume a large amount of space, causing the systems to be unwieldy to transport and to require a substantial amount of labor to install. Third, such systems typically are not available for household use. Although prior wastewater treatment systems may include a combination of known components for treating wastewater (see e.g., U.S. Pat. No. 4,687,574 to Hellman), these systems do not provide a compact, one-piece unit that houses all the components necessary to efficiently convert a household wastewater stream into an effluent that is suitable for above-ground discharge. Thus, there is a need for a compact, efficient wastewater treatment system for household wastewater.